Along with the semiconductor manufacturing process entering the era of nanotechnology, the traditional photolithography is confronted with the predicament, the physical extremity of the optical wavelength. Therefore, finding a substitution technology with low cost and high production thus becomes the key point in the next generation researches. Wherein, the nano-imprint lithography possessing the characters of thin line width, low cost, and high production is considered as the main stream of the next generation lithography technology. Meanwhile, the related patents are quickly accumulated.
The beginning of Nano-Imprint Lithography (NIL) applied in semiconductor manufacturing starts at 1996 when Dr. Stephen Chou published the noted paper, Imprint lithography with 25-nanometer resolution, Science 272, 85 (1996), of which the principle is like to stamp a template into the soft plastic. Please refer to FIG. 1A to 1C, which are the schematic views showing the standard semiconductor manufacturing process with Nano-Imprint Lithography. Firstly, a mold 11 having a particularly arranged pattern with protruding and recessing portions on its surface is formed by the lithography technology (such as mask, e-beam, focused ion beam, and so on). Then, a resist material 12, such as Polymethyl methacrylate (PMMA), is formed on the substrate 13. With appropriate temperature and pressure, the mold 11 is pressed onto the resist material 12 with the patterned surface thereof thus transferring the pattern of the mold surface to the resist material 12. Instead of the traditional photolithography method, the mold of such technology is processed with an energy beam system, which can easily improve the resolution attaining to the nano-level. Further, the nano-imprint lithography can reduce the process steps so as to uplift the throughput. In addition, the mold can be reused for many times and has longer lifetime than the traditional mask thus can large reduce the production cost.
However, the process of the mold belongs to the ultra precision technology that consumes lots amount of process time and production cost. Besides, in the imprinting process, the contact or even the collision between the mold and the substrate will cause certain attrition. Therefore, if the capability of antifriction of the mold is so worse as to need large quantity of alternate molds for replacing the damaged one, the application of nano-imprint lithography will suffer certain limitation. In addition, if the surface reaction force between the mold surface and the resist material is too large, when the mold is took off from the resist material, it will cause the mold to absorb certain residue thus resulting in not only the deviation of the device size but also the extra spending of the time and the cost for clean the mold surface. So, how to manufacture a mold with the characters of better antifriction and easily taking off from imprinted materials thus becomes a key point in the related researches.
In the IEEE Microprocesses and Nanotechnology Conference, 2001, the team of Japan Osaka Prefecture University disclosed a method to coating quartz and nickel onto the silicon mold surface. Moreover, Dr. Y. Tokano of TOKYO University of Science also published another technology using sapphire as the mold material to solve the aforesaid problems. Please refer to FIG. 2, which is the table comparing several physic characters of quartz, sapphire, silicon, and diamond. Obviously, in all the aspects of hardness, tension, heat conductivity, and thermal expansion coefficient, diamond is better than any other ones. Therefore, the present invention employs the diamond material as the principle part of the mold thus obtaining the objects of high antifriction and easily taking off from imprinted materials. Besides, corresponding to the appropriate process, the present invention can also provides the effects of cost reduction and mass production.